Compasses



of which the following is a specification;

`UNITED STATns PATENT OFFICE.

MILTON BRADLEY, OF SPRINGFIELD, MASSACHUSETTS.`

COMPASSES.V

SPECIFICATION forming part of Letters Patent No. 524,160, dated August7, 1894.

. Application filed April 11, 1894.

To alwhom tm/ty concern.-

Be it known that I, MILTON BRADLEY, a

siding at Springfield, in the county o'f Hampden and State ofMassachusetts, haveinvented new and useful Improvements in Compasses,

This invention relates to compasses for the j e use of draftsmen andstudents, the object be- .e IS

ing to improve the construction of such instruments in respect to theleg-joint thereof, to means on one of the-legs for holding and Operatinga pencil and to means for `uniting a steel point to the other leg, allas hereinafter fully set forth.

In the drawings forming part of this speciication, Figure l isaperspective view of a pair of Compasses Vembodying my improvements, apencil being there shown connected to one of the legs thereof. Fig. 2illustrates,

. vin perspective views, the handle and the jointpin and `nut of theinstrument, and the spanner for turning said nut. Figs. 3 and 4 areperspective views of the'upper ends of the two legs ofthe compasses,illustrating the joint formation of each leg. Fig. 5`is a longitudinalsection of the lower end of the peni cil-carrying leg. Fig. `6 is a sideview of the e lower end of said last named leg, showing the V3,0

front side of the pencil tube broken away at Yits lower extremity. Fig.7 is an end view of l the pencil-tube and a cross sectional view of theleg'thereto connected. Figs. 8 and 9 are y sectional views about on line9 9, Fig. 1, of 35 the point-bearing leg, illustrating the` manner ofsecuring the point rigidly in the leg.

In the drawings, 2 indicates the point-bearing leg, and Sthepencil-bearing leg of the instrument. The 4joint-parts of said legs areconstructed as follows: 0n the upperl end of one leg, 2, for instance,is a circular, platelike formation, a, havingthe kcentral bolthole, b,and the concentric vupstanding ring, c, on the inner side of said plate,located about-'midway between the border and the center of the latter.On the upper end of the opposite leg of the instrument, 3, is a similarcircular plate, cl, having` also a central bolt-hole, e, correspondingto said hole, b, of the leg, 2, and having a concentric circular groove,f, in its inner face of such width, diameter, and depth, as adapts it toreceive sition.

Serial No. 507,087. `(No model.)

. therein the said projecting ring, c, of the leg, 'i

ring and said groove are brought into j uxtapo- The said ring, c, andgroove, f, are formed with most-carefully adjusted tools, to the endthat the ring shall f it perfectly into the groove, thus bringing thesaid inner surfaces of the plates, a and d, so that they bear oneagainst the other, and, together with the said interengagement of thering, c and the groove,

f, constitute such a wide bearing for the joint parts of the compasslegs that great durability of the joint is secured, and there y,is notendency to looseness and consequent inadvertent displacement `of the`legs when adjusted to certain relative positions of spread', andwhilebeing used.

. The handle, K, of the instrumen-t consists. y

of a metallic tube, 4., to which` are secured two metal disks, 5, eachhavinga laterally extending arm, 6, on its border which enters and issecured to the inner surfaceof 4the' tube, K, by solderingor othervsuitable means. The said disks are perforated to correspond with saidbolt-holes, b and e, of the joint parts i -of the compasses As shown inFig. 1, the head (or united joint parts) of `the instrument isclaspedbetween said disks, 5,and a joint-bolt, 7,'.Whose diameter isless than that of said bolt-holes,

8. Said bolt, 7,'is made to fit loosely in said bolt-holes so that itmay act together with Y said nut, simply to prevent any separation of"the surfaces of said joint-parts onwhich are the said interlocking ring,c, and groove, f;

and so that said bolt shall not exercise any 1 function of an ordinary joint-pivot, and thereby prove an obstacle to the proper free coac-A tionof said grooves of the joint.

and ring-bearing parts g The legs, 2 and 3,'of the compass'es areprefj,

erably made of brass, or similar easy-working metal, and to provide asuitable hard and t durable point on the free end of one of "thelegs,`which shall serve the usual and well known purpose, a pointedsteel rod, 9, is rig- Ico idly ixed in said leg in the following manner:Said leg, from its lower end upwardly, has a groove, 10, formed thereinof suitable length,'and in said Vgroove said rod, 9, is

placed, and the borders, x, of said groove are then pressed, orswaged,over, and rigidly upon said rod, thereby permanently fixing it tosaid leg, as shown in Fig. 1.

To provide means for holding a pencil, 71,

`'on one leg of the compasses, and means for accurately advancing saidpencil in the dij rection of its length, as its point is Worn, or

Vthe surface of the pencil. Said dog is pro-l cut away by sharpening it,a split metallic tube, l2, is soldered, or otherwise suitably xed, tosaid leg, as shown, which slightly expands when the pencil is put intoit, and o n said tube, preferably at the lower end thereof,

is xed, or bent therefrom, a dog, 13, havingl an edge thereon suitablefor engaging with A short split tube, J, is fixed on said leg, 3, a j

little above said tube, 12, to aid in holding the pencil which passes through it more steady While it is turned to feed it forward and back. Thesaid dog, 13, holds the pencil positively against slipping in the tube,12, and the angularly arranged dog ou the latter provides for veryfinely graduating the movement of the pencil. In practice it is foundthat said screw-feed movement of the pencil through the tube results inmarking the latter with spiral convolutions, as shown in Fig. 1.

What I claim as my invention is- 1. A uniting joint for compass legs,consistving of a circular plate on one leg having therein a circulargroove concentric With a central bolt-hole through said plate, combinedwith a like` plate on the opposite leg of the compass having thereon anupstanding ring concentric with the central bolt-hole through said plateand fitting closely Within said groove, a handle having two-perforateddisks thereon between which said joint-plates are received, and ajoint-bolt passing through said joint-plates and disks and holding theparts through which it passes in juxtaposition, substantially as setforth.

2. A uniting joint for compass legs consisting of a circular plate, d,having the central bolthole, e, and the concentric groove, f, therein,combined with the circular plate, d, of the opposite leg having thecentral bolthole, b, and the upstanding concentric ring, c, thereon forengagement within said groove, a handle, and a bolt holding saidjoint-parts in juxtaposition, and said handle thereon, substantially asset forth.

3. Means for holding and operating a pencil on a compass-leg consistingof a split tube rigidly fixed thereto to receive a pencil, having apencil-engaging dog thereon projecting inwardly and standing at anincline relative to the axial line of said tube, substantially as setforth. v

4. Means for holding and operating a pencil on a compass-legconsistingof a split tube rigidly fixed thereto to receive a pencil, having apencil-engaging dog thereon projecting inwardly and standing at anincline relative to the axial line of said tube, combined with 'a secondsplit pencil-guiding tube fixed on 5. A uniting joint for compass legsconsisttion, and said handle thereon, substantially as set forth.

MILTON BRADLEY.

lVitnesses:

I-I. A. CHAPIN, K. I. CLEMoNs.

